The Malema M-VF safety excess flow valve is engineered for fast automatic shut-off in case of line, hose, or fitting failures, protecting employees, plant and valuable instruments. The M-VF comes in five port sizes, 1/8", 1/4", 3/8", 1/2", and 3/4" sizes, and the option to chose a KFM or FFKM O-rings for chemical compatibility. Designed for protection of systems handling corrosive, toxic, radioactive and flammable materials; the valve instantly detect a surge in the system and stop fluid flow. When the line break is repaired and pressure is equalized in the system, the valve will open to allow the fluid to flow through the system. The M-VF operates effectively with all fluids, liquids, and gases.

As the fluid (liquid or gas) enters the valve, the Pressure differential across the piston creates a venturi effect, accelerating the flow through the valve. At a preset flow rate, when the differential exceeds the magnetic attraction between the piston magnet and the adjusting screw magnet, the piston travels instantaneously over towards the output port, thereby shutting off the flow. When the pressure is equalized between both sides of the valve, the piston automatically returns to its previous adjusted flow setpoint. The shut off point is field adjustable and this is achieved by turning the adjusting screw.

Applications include pollution control, leak detection, hydraulic lines, regular protection, compressed air and gas systems, gas analyzers, sampling station operator protection, and catastrophic failure protection.